Cementing plug



E. V. CROWELL CEMENTING PLUG Dec. l2, 1933.

, original Filed July 2s A TTORNEY.

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Patented Dec. l2, 1933 UNITED STATES PATENT oFFicE CEMENTING PLUG Erd V.Crowell, Los Angeles, Calif.

10 Claims.

This invention hrelates to cementing plugs adapted for use in cementingoil wells and the like, the present application being a division of mycopending application Ser. No. 208.539, filed July 26, 1927, which hasissued as U. S. Patent No. 1,828,099, granted October 20, 1931.

It is an object of the invention to provide a plug adapted forconvenient insertion and subsequent withdrawal from a usual string ofwell casing so as to again present an unobstructed casing bore after acementing operation.

It is a further object of the invention to provide a plug which willnormally completely close the bore of the well casing but which isadapted to be readily opened for drainage therethrough when the plug issubsequently withdrawn from the casing.

Further objects of the invention will be readily understoodfrom thefollowing description of the accompanying drawing, in which:

Fig. 1 is an axial section through a string of Well casing, showing theimproved plug being lowered to operative position.

Fig. 2 is a similar view showing the plug in operative position.

Fig. 3 is a similar view showing the method ol' withdrawing the plug.

Fig. 4 is a transverse section on the line 4 4 of Fig. 2.

For purpose of illustration the improved plug is described in connectionwith a cementing apparatus which includes a xed section l of a string ofcasing A which is adapted for reception in well bore B. The section 1 isplaced in the string of casing at any predetermined level and preferablyhas a bore of slightly greater diameter than the remainder of thestring; and at its lower end the section 1 may be connected to thestring by a coupling 2 forming an internal supporting shoulder 3.Medially of its length the bore of the xed section preferably forms anundercut shoulder 4, and ports 5 open through the Wall of the fixedsection just below this undercut shoulder. The ports 5 are normallyclosed by a r sleeve valve 6 slidable in the lower end of the bore ofsection l with the bore of the sleeve valve forming a uniformcontinuation of the bore of the string of casing; and the sleeve valveis yieldably shifted upwardly to close the ports and abut againstshoulder 4 by means of a coil spring '7 upon which the sleeve valverests and which is in turn supported upon shoulder 3.

The spring 'l retains the sleeve valve inelevated, closed positionirrespective of pressure in the string of casing, but the sleeve isadapted to (Cl. 16S-1) be loweredV against the tension of its spring soas to open ports 5, by means of 'an actuating plug which is lowered inthe string of casing so as to' engage by resting upon and depress sleeve6 and then anchor on the sleeve with the ports open.

The actuating plug when thus anchored opens thel ports and then closesthe bore of the casing just below the open ports 5, and as a consequencea cementing mixture introduced into the string of casing in back of theanchored plug is prevented from flowing downwardly through the casingpast the plug and is discharged through open ports 5 into thesurrounding well bore. A predetermined quantity of the cementing mixtureis preferably thus discharged through the open ports, the quantity ofcement being measured by a traveling plug lowered in the casing in backof the cement, and in order to prevent leakage past either the actuatingplug or the traveling plug they are preferably each provided withsuitable packing shown at 8 whereby they. form a fluid-tight but slidingflt in the well casing.

The plugs are adapted to beremoved subsequent to the cementing operationso as to again provide an unobstructed casing bore, and for 30 thispurpose both the actuating plug 9 and the traveling plug 10 may berecovered from the well by use of a suitable tool; and the plugs arepreferably provided with normally closed valves which are adapted toopen when the plugs are g5 withdrawn so as to allow any fluid above theplugs to pass therethrough and thus eliminate all swabbing action.

4As an instance of this arrangement the plugs 9-10 have open bores 11provided with valve 90 seats 12 at their lower ends, and valves 13 areadapted to normally engage the valve seats for closing the bores vof theplugs. The valves are retained in closed position by pressure above theplugs as they are lowered in the well casing, but when the plugs arewithdrawn the valves are lifted to open position by operatively engagingtheir valve stems 14. The valve stems are hollow tubing extendingupwardly from the valves and sliding in guides 15 at the upper ends ofthe 100 hollow bores of the plugs, and these stems are adapted forengagement by-a usual tubing spear C as shown in Fig. 3 when the plugsare to be Withdrawn, so that elevation of the valve stems will firstopen valves 13 and then Withdraw the 105 plugs by engagement ofdepending abutments 16 of the valves against the undersides of valveseats 12.

The actuating plug 9 may be provided with peripheral abutment slipswhich are adapted to automatically expand when the plug has been loweredinto the slightly enlarged bore of section 1 in order that said slipsmay rest against sleeve valve 6 for depressing the same to open ports 5and then anchorthe plug on the sleeve for closing the bore of thecasing. These abutment slips' are shown in Figs. 2 and 4 as a pair ofarcuate slips 17 which are adapted to contract on plug 9 as the plug islowered through the string of casing, and springs 419 are positioned inback of the slips so as to yieldably urge the same to expanded positionwhere they will operatively engage sleeve valve 6.

In addition to the positive closure means for ports 5 which is formed bythe sleeve valve 6 opening only through engagement by the actuatingplug, the ports may be provided with auxiliary closure means attheexterior of section 1 of the casing, the said auxiliary closure meansbeing adapted to open by pressure of material discharged outwardlythrough ports 5 when sleeve valve 6 has been opened, but automaticallyclosing against back flow of material through the ports and into thecasing irrespective of the position of valve 6. The auxiliary closuremeans are shown as spring strips 25 fixed at one end to the exteriorsurface of casing section 1, with the opposite swinging ends of thestrips overlying and normally closing ports 5. Pressure of materialdischarged outwardly through the ports is thus adapted to swing thestrips outwardly as shown in Fig. 2 for opening the ports, but as soonas all the material has been discharged through the ports the resiliencyof the spring strips again closes the same to prevent back flow into thecasing.

In operation the plug 9 is adapted to be lowered in the well casing asshown in Fig. 1, and when the plug reaches the valve sleeve 6 it restsupon and depresses'the same to open ports 5, and by anchoring on thedepressed sleeve valve it then closes the bore of the casing below theopen ports, the parts in this position being shown in Fig. 2. Thecementing mixture follows plug 9 into the casing, the quantity of cementbeing measured by lowering the traveling plug in back of the same, andthe traveling plug is forced downwardly in suitable manner so that thecement flows outwardly through the open ports, the auxiliary valves 25readily opening by th'e pressure ofv the flow for discharge of thecement into the surrounding well bore. The cement having been dischargedthe valves 25 automatically close to prevent back flow into the casing,and -the plugs may then be immediately removed as previously describedwhile the cement is yet plastic, whereuponthe valve 6 will again closeand the string of casing will thus provide a usual cemented well.structure with the bore of the casing unobstructed and the ports in itswall positively held in closed position irrespective of pressure in thecasing.

During said withdrawal of the plugs 9-10 their valves 13 will be shiftedfrom normal closed position to open position as shown in Fig. 3, and theplugs thus normally present barriers for the entire cross-sectional areaof the casing,A but -are adapted for ready engagement and withdrawal,and provide open passageways through the plugs during said withdrawal soas to permit free drainage of iluid.

l. A plug adapted to be lowered in well casing and snugly engage thewall of the bore of the casing for confining material which is adapted.gagement by a tool to open the valve and withfor discharge into thesurrounding well bore, said plug having a bore, and a valve normallyclosing said bore and adapted for engagement by a tool to open the valveand withdraw the plug from the well casing.

2. A cementing plug adapted to snugly engage the Wall of a bore andhaving an axial bore opening through the plug, and a valve normallyclosing the bore of the plug and adapted for endraw the plug.

3. A plug adapted lto be lowered in a well, the plug having a bore, avalve seat at'the lower end of said bore, a valve normally engaging theseat for closing the bore, and a hollow valve stem projecting upwardlyfrom the valve and slidable in the bore, said hollow valve stem beingadapted for engagement by a tool for opening the valve and withdrawingthe plug from the well.

4. A plug adapted to be lowered in a well, the plug having a bore, avalve seat at thelower end of said bore, a valve nam'ally engaging theseat for closing the bore against downward flow, a valve stem projectingupwardly from the valve and slidable in the bore, and a guide for thevalve stem spaced from the wall of the bore so as to leave a passagewaythrough said bore.

5. A plug adapted to be lowered in a well so as to snugly engage thewall of the well, means on the plug for anchoring said plug in the well,the plug having a bore, a valve normally closing said bore, and meansfor opening said valve and withdrawing the anchored plug from the well.

6. A plug carrying means slidingly fitting a well casing and adapted tobe forced by iluid pressure downwardly therethrough to actuate valvularmeans controlling ports in said casing, said plug carrying meanscooperating with means attached to said casing to anchor said plug at apredetermined point therein, said plug having a bore, a valve normallyclosing said bore against downward ow, and means for opening said valve.

7. A plug carrying means snugly engaging the bore of a well casing andadapted to be forced by fluid pressure downwardly therethrough, means insaid Well casing cooperating with means on said plug to anchor thelatter at a predetermined point within said well casing so as to closeoiT the bore of said well casing therebelow, a bore in said plug, avalve normally closing said bore against downward ilow, andan operatingconnection for opening the valve while the plug is anchored in the well.l

8. A plug carrying means forming a duid-tight sliding engagement with.the bore of a well casing 130 and adapted to be forced downwardlythrough said casing by iluid under pressure, means on said plugcooperating with means in said casing for arrestingthe downward movementof said plug at a predetermined point within said casing, a 135 bore insaid plug, a valve normally closing said bore against downward ow, andmeans carried by said valve for opening the same and facilitating thewithdrawal of said plug from saidwell casing.

9. A barrier for mud fluid and cementing mixture adapted to be forceddownwardly through a well casing by fluid under pressure and in itsdownward course to force the iluid before it into the space outside ofthe casing, said barrier car- 145 rying means cooperating with meanswithin said casing to arrest its downward movement at a predeterminedpoint within said casing so as to close of! the bore therebelow, a borein Said barrier, a valve normally maintaining closure of 150 1,css,css

ling ports in said casing and also carrying means cooperating with meanswithin said casing to arrest the downward movement o! said barrier at apredetermined point within said casing so as to close off the boretherebelow, la bore in said barrier, a valve normally maintainingclosure of said bore, and means for opening said valve and removing saidbarrier from said casing.

ERDV.

